Heating system.



affozncq anon H01 Patented @ept. 11, 191?.

W. T. MIXSELL.

HEATING SYSTEM. APPLICATION FILED Aue.4, 191s.

I WD TEMPLE MIXSELL, OF WASHINGTON, DISTRICT OF COLUMBIA.

HEATING SYSTEM.

Specification of Letters Patent.

rateetea Sept. ii, row,

Application filed August A, 1916. Serial No. 113,089.

To all whom it may concern:

Be it known that I, WARD T. MIXSELL, a cltizen of the United States, residing at Washington, District of Columbia, have invented certain new and useful Improvements in Heating Systems, of which the 01- lowing is a specification.

This invention relates to an improvement in steam heating apparatus, particularly that class of apparatus known as vapor systems, which are operated at a low pressure, and in which the condensation from the radiating surfaces is returned to the steam supplying source by gravity due to the difa pressure in the boiler greater than the static head would prevent the direct or gravitation return of the condensation, with a consequent waterlogging of the return pipes and attached radiators, and when such an excess pressure continues, the water in the boiler may be sufficiently evaporated to burn and ruin or explode the same.

To overcomethis trouble use has been made of enlarged diaphragm and float type damper regulators, in the endeavor to control the fire and the resulting steam pressure within the limits of the hydrostatic head, but these means have proved impractical and insuficient to prevent damage to the boiler, or the waterlogging of the system interfering with a free circulation from the radiating surfaces.

The object of this invention is to'provide means for so equalizing the relative pressures existing between. the boiler with its supply piping and the return piping, that the dlfi'erence of pressure, existing between the same will equal the specific static head .irrespective of the pressure in the boiler or steam supplyingsource, so that when the pressure in the boiler etc., 1s less than that of the specific static head, the return main may be open to the atmosphere, for the free venting of the system, and when the boiler pressure rises above that pressure which s equal to the static head, a main air vent is closed by a valve, sealing the system, and then steam is admitted to the return mains, through a weighted valve, so as to equalize the pressures, and permit a continuous return of the condensation to the boiler. The equalizing valve is weighted to open, under a diflerence of pressure in the boiler or supply main, and the return main, equal to the pressure of the static head, and the air venting valve may be closed either before or after the opening of the equalizing valve. A further purpose of the invention relates to a specific method of piping and the location of the equalizing valve to prevent water hammer etc. as hereinafter described.

My method of pressure equalization is applicable to both systems of vapor apparatus, those in which a simple check valve or those in which a thermostatic valve is used at'the return or discharge opening of the radiators. Where a check valve is used, as steam may be discharged into the return main from the radiators, a thermostatic valve is required to close the main air vent and prevent normal loss of steam to the atmosphere, and further loss when the equalizing valve isopen admitting steam to the return main. When thermostatic valves are used at the radiators, as the normal steam leakage is negligible, a diaphragm operated valve 1s placed 1n the main air vent, the diaphragm being subject to the boiler pressure, and adjusted by lever and weights or spring tension to close, preferably before the equalizing valve opens.

A vapor heating apparatus constructed in accordance with my method, may include a boiler, supply mains, radiator branches,

etc., a valve of the multiport or registering type for graduating the flow of steam or vapor to the radiators, a check valve or thermostatic valve at the return end of the radiators, a system of return piping, a receiver into which the condensation and air from the radiating surfaces is discharged, a vent opening to the atmosphere, controlled by a mechanically or thermostatically operated valve, and a check valveeither inside or out.

side the main vent valve for the purpose of excluding air from the system, permitting a continuance of steam circulation below atmospheric pressure, and a. weight or a spring controlled equalizing valve forming a connection between the steam main and the return main. If this connection were made directly to the receiver from the boiler it would suifice to effect the desired pressure equalization so as to return the condensation to the boiler, but as a lower pressure would exist in the returnlines leading to the receiver, the water in the lines would be backed up causing a water hammer, and a flooding of the system at't-he extreme ends of the return lines. To prevent this, the equalizing valve is connected to the extreme or starting end of the return, so that when the valve opens the steam will drive the water in the return toward the receiver.

When possible the piping is arranged on the circuit plan, the steam main continuing full size around the building, and to equalize the pressure of circulation throughout the system the return main starts at the first radiating surface supplied by the steam main and runs parallel to the same, so that the radiators nearest the boiler are farthest from the air vent, one equalizing valve being used and one vent valve. When several circuits are required, one set of valves may be used, but different circuits can be valved separately to accomplish specific equalizations of pressure due to differences in pressure losses in the various circuits.

With my system any pressure may be generated within the system, and the continuous return of condensation will be accomplished whether operating above or below atmospheric pressure. This system therefore permits a greater range in the operating pressure, and is less dependent on damper regulator control, for maintaining a pressure above the pressure of through circulation, overcoming the sensitiveness of other vapor systems.

One embodiment of my invention is illustrated in the accompanying drawing, in which Figure 1, is a diagram of a system, Figs. 2, 3 and 4 are details of valves used therein.

Referring to the drawing, 6 indicates the boiler, and a steam or vapor supply main leading therefrom, and connected to the inlet end of the various radiators 8 by means of risers or connections 9, each of which may be provided with a graduating supply valve 10. The main returns to the boiler below the water level thereof as indicated at 11, forming a steam or vapor circuit.

From a point preferably adjacent the first radiator, an air and water return main 12 extends parallel to the supply mainand leads to the upper end of a standing receiver 13 located beside the boiler, and connected at its lower end to the pipe 11 leading to the boiler by means of a pipe 14 having a water check valve 15 therein. The lower end of the receiver is substantially at the same'height as a normal water line indicated at 16 in the boiler. The receiver may have a gage 17. The upper end of the receiver main 12 by a pipe 21 provided with a return valve 22 which may be either of the check or thermostatic type. Between the first return connection 21 and the supply main 7, the return main 12 is provided with an equalizing valve 23 best shown in section in Fig. 3 which is normally closed but which may be opened by steam pressure.

The static head depends on the weight of water in the receiver 13, which, as shown, extends above the water line of the boiler. In operation, when the boiler pressure is less than the head referred to, the air vent valve 19 being open and the equalizing valve 23 being closed, the vapor or low pressure steam is supplied through the main 7 to the re spective radiators, and the water of condensation returns from the radiators through the line 12 to the receiver and thence to the boiler through the connection 11, which latter also returns the condensation from the pipe 7. When the. boiler pressure rises above the pressure of the static head the valve 19 closes, thereby sealing the system, and the equalizing valve 23 opens, thereby equalizing the pressure in the pipe 7 and the return pipe 12, and, under suchconditions the water of condensation will return by gravity from the radiators to the receiver and the boiler. The equalizing valve 23 is so adjusted or constructed with respect to the static head of the receiver that when the boiler pressure exceeds said head the valve will open toadmit steam pressure to the return .side of the system.

It will be noted that the equalizing valve 23 is located at the beginning "of the return main, and in advance of all of the return connections from the radiators. The return main 12 is also connected near its discharge end with the return end of the main 7 by a small pipe 25 having an air valve 24: best shown in section inFig. 4, to vent the air from the main 7 to the return main 12 and thence to the main air vent valve 19. The water checkvalve 15 opens downwardly or toward the boiler. The individual radiating naeaeoa all pressure conditions, since at low" pressure the static head provided by the receiver 13 will force the returnwater to the boiler, by gravity, and when the pressure increases above said head the equalizing valve will admit steam pressure to the inlet end of the return main, thereby equalizing the pressure, and tending by its flow to return the condensation to the receiver, the static head of which will continue to produce the return flow and prevent trapping in the system with resulting low water and danger to the boiler. V

It will be noted that the control is automatic and suitablefor all conditions either I above or below atmospheric pressure.

What I claim is:

1. In a heating system, the combination with, a boiler, radiators, and a supply main between the former and the latter, said main being connected at both ends to the boiler, of a'separate return line from the radiators to the boiler, a connection between the supply-and return mains, and a pressure-actuated equalizing valve in said connection adapted to admit steam to the return line in advance of the radiating system when-the pressure exceeds a certain amount, and to, exclude steam therefrom when the pressure is below said amount.

2. In a heating system, the combination with a boiler, radiators, and a supply main from the former to the latter, said main being connected at both ends to the boiler, of a separate return-line from the radiators to-the boiler, said line being. connected at one end to the supply main in advance of the return connections fromtthe radiators, a pressure-actuated equalizing valve at said end to admit steam to said line, and a receiver in said return line, extending above the normal water linein the boiler, to'pro- I vide a static head for the return of, water to the boiler. I r

3. In a heating system, the combination of av boiler,- radiators, a supply main from the former to the latter, said main being connected at both ends to the boiler, a receiver extending above the water line of the boiler and connected at its lower end therer to, a separate return line from the radiators, connected at its inlet end, in advance of the radiators, to saidsupply main and discharging at its' outlet end to the receiver, an air-vent valve in said'return' line, at the discharge end thereof, and a pressure-actuat d equalizing valve at the inlet end of said n e controlled by the pressure in the siiugiply main to admit steam to the return 4. In a heating. system, the combination with a boiler and radiators, of a supply main from the former to the latter, a return main from the radiators to the boiler, said return main having an air vent open at low pressure, a connection between the supply main and'the end of the return main in advance of theradiators, provided with a pressure-actuated equalizmg valve actuated by difl'erence in relativepressnres in the supply and return mains, and a pressure-operated valve controlling said air vent and adapted to close the same when the pressure exceeds a certain amount.

5. In a heating system, the combination of a boiler, radiators, a supply main from the former to the latter, a receiver extending above the water line of the boiler and connected at its lower-end thereto, a sep arate return line from the radiators, connected at its inlet end in advance of the radiators to said main and discharging at its. outlet end to the receiver, an air vent valve in said return line, at the discharge end thereof, and a normally-closed equalizing valve at the inlet end of said line, said valve adapted to be opened by pressure in the supply main and having a resistance substantially equal to the static head in the receiver, whereby the valve will be opened when the pressure equals said static head.

6. In a heating system, the combination of a boiler, a supply circuit main connectedat opposite ends to said boiler, a radiator having an inlet connection from said main, a separate return main connected to said radiator, and to said supply main in advance of said radiator connection, a presturn line discharges, an air vent valve at the. top of said receiver, and'a pressure controlling connection between the boiler and said air vent valve and adapted to close the latter whena certain pressure is reached.

In testimony. whereof, I afix my signature.

v WARD WXSELL- 

